2. Database & Information Systems8
Chapter
Database & Information Systems
8.1 Managing Files: Basic Concepts
8.2 Database Management Systems
8.3 Database Models
8.4 Data Mining
8.5 Databases & The Digital Economy
8.6 Using Databases to Help Make Decisions
8.7 Artificial Intelligence
8.8 The Ethics of Using Databases
McGraw-Hill/Irwin
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.

3. Managing Files: Basic Concepts
A database is a logically organized collection of related data designed and built for a specific purpose
Data is stored hierarchically for easier storage and retrieval
Files: collections of related records
Records: collections of related fields
Field: unit of data containing 1 or more
characters
Character: a letter number or special
character made of bits
Bit: a 0 or 1

4. Managing Files: Basic Concepts
Key Field – the field that identifies a record
Often an identifying number, such as social security number
Primary keys must be unique
Keys are used to pick records out of a database
Unique keys make records stand out from each other
If two records had the same key, then you might not pick the correct one
Nonprimary keys are used to sort records in different ways
Foreign keys are fields that appear in two different tables and are used to relate one table to another

5. Managing Files: Basic Concepts
This example shows a sample database in Microsoft Access. Products is a table. ProductID is the primary key of the Product table. ProductID is also a foreign key in the Orders table

6. Managing Files: Basic Concepts
Program files are files containing software instructions
Source program files are written by the software developer in the programming language
Double-clicking on them won’t run them
They have file extensions like .cpp, .jav, .bas
Executable files are program files translated so they can be executed on the computer
Double-clicking on them will cause them to run
They have file extensions like .exe or .com

7. Managing Files: Basic Concepts
Data files are files that contain data such as words, numbers, pictures, or sounds
These are the files that are used in databases
They have extensions such as .txt .mdb, and .xls
Graphics files have extensions like .tiff, .jpeg, and .png
Audio files have extensions such as .mp3, .wav, and .mid
Animation/video files have extensions such as .qt, .mpg, .avi, and .rm
Data files are often compressed to save space and transmit them faster
Compression removes repetitive elements from a file

8. Database Management Systems
Software written specifically to control the structure of a database and access to the data
Reduced data redundancy
Redundant data is stored in multiple places, which causes problems keeping all the copies current
Improved data integrity
Means the data is accurate, consistent, and up to date
Increased security
Limits who can create, read, update, and delete the data
Ease of data maintenance
Offer validation checks, backup utilities, and procedures for data inserting, updating, and deletion

9. Database Management Systems 3 Principal Components
Data Dictionary
A repository that stores the data definitions and descriptions of the structure of the data and the database
DBMS Utilities
Programs that allow you to maintain the database by creating, editing, deleting data, records, and files
Also include automated backup and recovery
Report Generator
Program for producing an on-screen or printed document form all or part of a database

10. Database Management Systems Database Administrator
Database Administrator (DBA)
A high-paid, responsible position within an organization
Coordinates all related activities and needs for an organization’s database
Ensures the database’s
Recoverability
Integrity
Security
Availability
Reliability
Performance
Discussion Question: Did you know that 93% of companies that lost their data center for 10 days or more due to a disaster filed for bankruptcy within a year?

11. Database Models Hierarchical database Network database
Relational database
Object-oriented database
Multidimensional database
Fields or records are arranged in a family tree, with child records subordinate to parent or higher-level records
Like a hierarchical database, but each child record can have more than one parent record
Relates, or connects, data in different files through the use of a key, or common data element
Uses objects (software written in small, reusable chunks) as elements within database files
Models data as facts, dimensions, or numerical measures for use in the interactive analysis of large amounts of data

12. Database Models Hierarchical Databases
Fields or records are arranged in related groups resembling a family tree with child (low-level) records subordinate to parent (high-level) records
Root record is the parent record at the top of the database, and data is accessed through the hierarchy
Oldest and simplest; used in mainframes

13. Database Models Network Database
Similar to a hierarchical database, but each child record can have more than one parent record
Used principally with mainframe computers
Requires the database structure to be defined in advance

14. Database Models Relational Database
Relates or connects data in different files through the use of a key, or common data element
Examples are Oracle, Informix, Sybase
Data exists independently of how it is physically stored
Users don’t need to know data structure to use the database
Uses SQL (structured query language) to create, modify, maintain, and query the data
Query by Example uses sample records or forms to allow users to define the qualifications for choosing records

15. Database Models Object-oriented Databases
Use “objects”, software written in small, manageable chunks, as elements within data files
An object consists of
Data in any form, including audio, graphics, and video
Instructions on the action to be taken with the data
Examples include FastObjects, GemStone, Objectivity DB, Jasmine Object Database, and KE Express
Types include
Web database
Hypermedia database

16. Database Models Multidimensional Database
Models data as facts, dimensions, or numerical answers for use in the interactive analysis of large amounts of data for decision-making purposes
Allows users to ask questions in colloquial English
Use OLAP (Online Analytical Processing) software to provide answers to complex database queries